Numerous such plastic containers are known. These plastic containers have different filling volumes. Furthermore compressible containers of which the contents can be removed by compression of the container are known. In such a tap system of the applicant PET bottles (BEVkeg) are emptied by deforming the container wall and the container shoulders. For this targeted deformation, in which in particular a mouth region of the containers is pushed into a base region of the containers, shaping parts (in particular dies) which are specially adapted to the container are used in the tap system. These shaping parts are designed on one side as a die, in order to push the container wall inwards and on the other side of the container these shaping parts are formed as supporting cups in which in particular a base region of the plastic containers to be emptied is located. Thus these shaping parts are integrated in a tap system and therefore are also co-ordinated with the respective container shape and container size. Replacement of these shaping parts is possible but only with relative difficulty, which in particular also significantly impedes a changeover to other containers.